基于像素值排序的可逆信息隐藏算法

针对嵌入秘密后灰度图失真明显的问题，提出一种基于像素值排序（PVO）的可逆信息隐藏算法。首先，将像素分成灰、白两层，选择灰层的像素作为目标像素，对目标像素十字交叉位置上的4个白色像素进行排序；然后根据排序结果计算两端两个像素的均值和中间两个像素的均值，利用可逆约束实现像素的动态预测；最后，根据预测结果构造预测误差直方图（PEH），使用环形复杂度实现秘密数据的自适应嵌入，并用同样的方法处理白色层像素。利用USC-SIPI标准图像库中6幅图像进行仿真实验，当嵌入容量（EC）为10000 b，平均峰值信噪比（PSNR）为61.89 dB时，该算法能有效减小携密图像的失真。

Reversible data hiding algorithm based on pixel value order

For the distortion of the image after embedding secret is excessively obvious, a new Reversible Data Hiding (RDH) based on Pixel Value Order (PVO) was proposed. Firstly, the pixels of a carrier image were divided into gray and white layers, the pixels of a gray layer were selected as the target pixels, and the four white pixels in the cross positions of the target pixels were sorted. Secondly, according to the sorting result, the mean value of the two end pixels and the mean value of the median pixels were calculated, and the reversible constraint was used to achieve dynamic prediction of pixels. Finally, a Prediction Error Histogram (PEH) was constructed according to the prediction result. Six images in the USC-SIPI standard image library were used for simulation experiments. The experimental results show that, when the Embedding Capacity (EC) is 10000 b and the average Peak Signal-to-Noise Ratio (PSNR) is 61.89 dB, the proposed algorithm can effectively reduce the distortion of the image with ciphertext.